Method and apparatus for determining subterraneous conductors.



H. R. CONKLIN.

METHOD AND APPARATUS FOR DETERMINING SUBTERRANEOUS CONDUCTORSI APPLICATLON FILED NOV-6,1916.

1 ,2}. 1 9'7, I Patented Sept. 25, 1917.

HARRY It. CQNKLIN, F JOPLIN, MISSOURI.

Mari-Ion Ann ArPAnA'rUs- FOIt nnrnnmnmesmsramaannoos conn ocrons.

6 have invented certain new and useful Imrovements in Methods and Apparatus .for etermining Subterraneous Conductors; and I do hereby declare the following to be a full, clear, and exact description of the 10 invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanyin drawings, and to letters or figures of re erence marked thereon, WhlCh form a part of this specification.

My invention relates to a method and apparatus for detecting electrically conductive bodies below the surface of the earth, such as bodies of electrically conductive ore, the

location of buried pipe lines and the like.

I have usedmy method and apparatus more particularly in locating ores which are electrical conductors, such as 'galena, pyrites, native gold, sulfid of silver, native copper,

copper sulfid, and the like.

In carrying out the method I produce an oscillating magnetic field whose axis is substantially perpendicular to the surface being explored by means of an oscillating 80 electric current, and explore this fieldto determine the contours within it of equal mag- "netic flux; the deviation of the contours in shape from the sha e of the line of induction for the magnetic field, by means of an ore body in said magnetic fieldTdetermmes the location of said ore body. he contour lines are properly plotted within the magnetic field to show their deviation in shape from the shape of the line of induction. In

40 other words, I determine the deviation of the oscillatin magnetic field from its 'normal, such devlation being produced by a subterraneous conductor.

I have found by practical experience that the presence of liquids and solutions does not 1cgiauge a distortion of the oscillating magnetic el the deviation in the line of e ual flux to determine the depth and quantity of the ore,

or to ascertain its character.

In carrying out my method I proceed as winding 8 of the transformer.

Bore holes are sunk in the area showing Specification of Letters Patent. Patented S pt, 25,, 191%, Application filed November 6, 1916. Serial No. 129,772.

follows, reference being had to the accompanymg drawing, in which 1 1s an alternating current generator from which run lines 2 and 3 to the primer coil ft of a transformer, there'being a regu ating inductlve resistance 5 included in the circuit. {In alternating current. ammeter .6 is also included inthe circuit, and across the circult 1s maintained an alternating current voltmeter 7. These two meters may be omitted, but they are desirable as indicators to determine the proper operation of the apparatus.

The primary coil 4 of the transformer acts on a secondary coil 8in the oscillating circuit, wlth which are connected in series condensers 9 and 10, and means for determining and producing an oscillating magnetic sub stantially annular field, as a wire loop or C911 11 of large diameter, which forms the hue of induction for the oscillating magnetic field.

The condensers, as will be seen, from the dlagram, are arranged one at each side of the loop or coil 11. A hot wire ammeter may be arranged for temporary series connection with the loop or coil 11, for determining the quantity of current flowing in the coil.

A spark gap 8 is included in the secondary circuit in parallel with the secondary This structure is substantially the equivalent of any Well known current structure for obtaining high oscillating current, the object being to cause said current to travel in a closed path through the loop or coil 11 to produce an osclllating magnetic field within the area of said coil. v v

The diameter of the coil or loop 11 may be varied to suit particular circumstances, but usually such 0011s or loops 11 are from about 200 to'lOOO feet in diameter. The shape of this coil or loop 11, which is laid upon the surface of the ground, is preferably, but not necessarily, approximately circular. Within this circle or loop 11 I have two exploring coils, 12 and 13, from about three to four feet in dlameter, the diameter bein proportion'ed to the amount of magnetic ux within the primary coil 11.

I have found that each exploring coil, 12 or 13, must consist of several turns of wire.

- These two coils, 1 2'and 13, are connected together by wires 14 and 15, and included in the wire 15 are crystal rectifiers '16, one on each side of a current indicator or galvanometer 17. The wires 14 and 15 are twisted together to prevent unequal induction in these exploring coil leads. For the same reason the coils 12 and 13, an'dltheir leads 14, 15 are made as nearly alike as practicable.

The exploring coils, current rectifiers and galvanometer are symmetrically arranged in series in a closed circuit, as shown, the exploring coils having their induced currents opposed to each other.

when the coil or loop 11 is laid on the ground and the high frequency oscillating current is sent through 1t, it produces a magnetic flux or field, perpendicular thereto, which reaches into the earth below. One

of the exploring coils, say for example, 13, is placed a definite distance from the center of the loop 11, and the coil 12 is moved around the loop so as to give a minimum galvanometer reading, and the path of the exploring coil 12 is then plotted. v

If a conductor, such as indicated at 0, be beneath the primary coil or loop' 11, the contour lines will be distorted, as shown at a, in the direction of said conductor.

In order to determine the area and outline of the ore body or the subterranean conductor O, the primary coil 11 is shifted until a suficient number of sets of contour lines have been observed to determine the outline, size, and approximate strength of the conductor, and if it be a body of ore, the degree of distortion of the contour lines is approximately a measure'of the density or richness of the ore.

After the size and contour of the ore body have been determined by the plotting of the contours, it is checked and the character of the ore determined by drilling.

A subterranean conductor, which is within a distance below the surface of a proximatel} two-thirds the diameter of t e primary coil, will measurably distort the contour lines of magnetic flux in .the plane of the primary coil.

Instead of using two exploring coils and the balanced mechanism above described, a single exploring coil may be used, to which is attached a telephone and a sin le current rectifier. The telephone will pro uce a hum similar to that in a wireless telephone receiver, and the variation of this sound is an indication of the variation of the intensity of the oscillating magnetic field within the loop 11.

I claim- Y 1. The method of determining a subterranean conductor, which comprises forming an oscillating magnetic'field at the surface 7 ing explored, exploring of the ground the axis of which field is substantially perpendicular to the surface be-- ing explored, and determining the distortion of said field due to the influence of the subterranean conductor. v

2. The method of determining a subterranean conductor, which comprises formmg at the surface of the ground an oscillating magnetic field the axis of which field is substantially perpendicular to the surface besaid field to determine contours of equal magnetic flux, the deviation of said contours in shape from the line of generation of said oscillating magnetic field determining the presence of the subterranean conductor.

3. The method of determining a subterranean conductor, which comprises forming an oscillating magnetic field at the surface of the ground the axis of which field is subositions of said coils for mmimum n I I ranean conductor, which comprises forming an oscillating magnetic field extending into the earth the axis of which field is substantially perpendicular to the surface being ex-.

plored, inducing in a pair of exploring coils in said field oscillating currents, rectifying said currents, and sending the rectified cur-- rents in opposition through a current indicator. l

5. The method of determining a subterranous conductor, which comprises forming an oscillating magnetic field extending into the earth and whose axis is substantially perpendicular to the surface being explored, inducing in a pair of exploring coils in said field oscillating currents, rectifying said currents, and sending the rectified currents in opposition through a current indicator and plotting the lines of equal magnetic flux in said field.

6. Apparatus for determining the location of subterranean conductors, which comprises means for producing and determining an oscillating magnetic field the axis of which field is substantially perpendicular to' the surface being explored, exploring coils movable in said field and connected together in series, a current rectifier for each coil and a I 10 plored, anexploring Winding movable within said field and means, and a current rectifier connected in electrical circuit with said winding and means electrically connected to said Winding and rectifier to detect variations of current in said Winding.

In testimony that I claim 'the foregoing as my invention, I have signed my name in presence of two subscribing Witnesses.

HARRY R. GONKLIN. 

